Microfluidic devices and methods of use

• US 20020127736A1
• Filed: 10/02/2001
• Published: 09/12/2002
• Est. Priority Date: 10/03/2000
• Status: Active Grant

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Chou, Hou-Pu, Quake, Stephen R., Fu, Anne Y.
• Granted Patent: US 7,258,774 B2
• Time in Patent Office: Days
• US Class Current: 436/180
• CPC Class Codes: A61M 2206/22 eliminating pulsatile flows, e.g. by the provision of a dampening chamber
• CPC Class Codes: B01L 2200/0647 Handling flowable solids, e.g. microscopic beads, cells, particles
• CPC Class Codes: B01L 2300/0816 Cards, e.g. flat sample carriers usually with flow in two horizontal directions
• CPC Class Codes: B01L 2300/0864 comprising only one inlet and multiple receiving wells, e.g. for separation, splitting
• CPC Class Codes: B01L 2300/123 Flexible; Elastomeric
• CPC Class Codes: B01L 2400/0418 electro-osmotic flow [EOF]
• CPC Class Codes: B01L 2400/0481 squeezing of channels or chambers
• CPC Class Codes: B01L 2400/0655 pinch valves
• CPC Class Codes: B01L 2400/084 Passive control of flow resistance
• CPC Class Codes: B01L 3/5027 by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip B01L3/5023 takes precedence; micromixers B01F33/30; microreactors for synthesis B01J19/0093; microcapillary devices in general B81B1/00
• CPC Class Codes: B01L 3/50273 characterised by the means or forces applied to move the fluids micropumps F04B19/006, of the membrane type F04B43/043
• CPC Class Codes: B01L 3/502738 characterised by integrated valves microvalves F16K99/0001
• CPC Class Codes: F04B 11/00 Equalisation of pulses, e.g. by use of air vessels; Counteracting cavitation
• CPC Class Codes: F04B 19/006 Micropumps F04B43/043 and F04B43/095 take precedence
• CPC Class Codes: F04B 43/00 Machines, pumps, or pumping installations having flexible working members pumps or pumping installations specially adapted for elastic fluids F04B45/00
• CPC Class Codes: F04B 43/043 Micropumps
• CPC Class Codes: F04B 43/14 having plate-like flexible members
• CPC Class Codes: G01N 15/149 specially adapted for sorting particles, e.g. by their size or optical properties
• CPC Class Codes: G01N 2015/1028 Sorting particles
• CPC Class Codes: G01N 2030/205 Diaphragm valves, e.g. deformed member closing the passage
• CPC Class Codes: G01N 2030/322 : pulse dampers
• CPC Class Codes: G01N 30/6095 : Micromachined or nanomachined, e.g. micro- or nanosize
• CPC Class Codes: Y10T 436/2575 : Volumetric liquid transfer

Abstract

A microfluidic device comprises pumps, valves, and fluid oscillation dampers. In a device employed for sorting, an entity is flowed by the pump along a flow channel through a detection region to a junction. Based upon an identity of the entity determined in the detection region, a waste or collection valve located on opposite branches of the flow channel at the junction are actuated, thereby routing the entity to either a waste pool or a collection pool. A damper structure may be located between the pump and the junction. The damper reduces the amplitude of oscillation pressure in the flow channel due to operation of the pump, thereby lessening oscillation in velocity of the entity during sorting process. The microfluidic device may be formed in a block of elastomer material, with thin membranes of the elastomer material deflectable into the flow channel to provide pump or valve functionality.

Claims

1. A microfluidic device comprising:

a flow channel;

a pump operatively interconnected to said flow channel for moving a fluid in said flow channel; and

a damper operatively interconnected to said flow channel for reducing the fluid oscillation in said flow channel.

2. The microfluidic device of claim 1, further comprising a flow control valve operatively interconnected to said flow channel for closing and opening said flow channel.

3. The microfluidic device of claim 2, further comprising a T-junction.

4. The microfluidic device of claim 3, wherein said T-junction comprises an injection pool, a waste pool and a collection pool interconnected by said flow channel, and wherein flow channel further comprises said flow control valve proximal to said waste pool and said flow control valve proximal to said collection pool, said pump proximal to said injection pool and said damper proximal to said injection pool but posterial to said pump.

5. The microfluidic device of claim 4 further comprising a plurality of said dampers.

6. The microfluidic device of claim 1 wherein the damper comprises a cavity separated from the flow channel by a flexible membrane, the flexible membrane deflectable into the cavity to absorb energy in response to pressure oscillation within the flow channel, thereby reducing an amplitude of the pressure oscillation.

7. The microfluidic device of claim 6 further comprising a constriction in a width of the flow channel positioned downstream of the flexible membrane.

8. The microfluidic device of claim 1 wherein the damper comprises an enlarged portion of the flow channel partially filled with a fluid, the fluid compressible to absorb energy in response to pressure oscillation within the flow channel, thereby reducing an amplitude of the pressure oscillation.

9. The microfluidic device of claim 1 wherein the damper comprises elastomeric material forming walls of the flow channel, the elastomeric material deflectable to absorb energy in response to pressure oscillation within the flow channel, thereby reducing an amplitude of the pressure oscillation.

27. A method for sorting a material using a microfluidic device of claim 4.

10. A microfluidic sorting device comprising:

a first flow channel formed in a first layer of elastomer material, a first end of the first flow channel in fluid communication with a collection pool and a second end of the first flow channel in fluid communication with a waste pool;

a second flow channel formed in the first elastomer layer, a first end of the second flow channel in fluid communication with an injection pool and a second end of the second flow channel in fluid communication with the first flow channel at a junction;

a collection valve adjacent to a first side of the junction proximate to the collection pool, the collection valve comprising a first recess formed in a second elastomer layer overlying the first elastomer layer, the first recess separated from the first flow channel by a first membrane portion of the second elastomer layer deflectable into the first flow channel;

a waste valve adjacent to a second side of the junction proximate to the waste pool, the waste valve comprising a second recess formed in the second elastomer layer separated from the second flow channel by a second membrane portion of the second elastomer layer deflectable into the first flow channel;

a pump adjacent to a third side of the junction proximate to the injection pool, the pump comprising at least pressure channels formed in the second elastomer layer and separated from second flow channel by third membrane portions of the second elastomer layer deflectable into the second flow channel; and

a detection region positioned between the injection pool and the junction, one of an open and closed state of the collection valve and the waste valve determined by an identity of a sortable entity detected in the detection region.

11. The microfluidic device of claim 10 further comprising a damper structure adjacent to the second flow channel between the pump and the detection region.

12. The microfluidic device of claim 11 wherein the damper comprises a cavity formed in the second elastomer layer and separated from the second flow channel by a flexible membrane, the flexible membrane deflectable into the cavity to absorb energy in response to pressure oscillation within the second flow channel, thereby reducing an amplitude of the pressure oscillation.

13. The microfluidic device of claim 12 further comprising a constriction in a width of the second flow channel between the flexible membrane and the junction.

14. The microfluidic device of claim 11 wherein the damper comprises an enlarged portion of the flow channel partially filled with a fluid, the fluid compressible to absorb energy in response to pressure oscillation within the flow channel, thereby reducing an amplitude of the pressure oscillation.

15. The microfluidic device of claim 10 wherein the elastomer material forming walls of the first flow channel is deflectable to absorb energy in response to pressure oscillation within the flow channel, thereby reducing an amplitude of the pressure oscillation.

16. The microfluidic device of claim 10 wherein the junction is T-shaped.

17. The microfluidic device of claim 10 further comprising a second sorter structure positioned between the waste valve and the waste pool.

19. The damper of claim 18 wherein the energy absorber comprises a flexible elastomer membrane positioned between the flow channel and a cavity, the flexible membrane deflectable into the cavity to absorb the energy of oscillation in the flow channel.

20. The damper of claim 18 wherein the energy absorber comprises a fluid positioned within an enlarged portion of the flow channel, the fluid compressible to absorb the energy of oscillation.

21. The damper of claim 18 wherein the energy absorber comprises elastomer material on the side walls of the flow channel, the elastomer material deflectable to absorb the energy of oscillation.

22. The damper of claims 19, 20, or 21 further comprising a constriction in a width of the flow channel downstream of the energy absorber.

24. The method of claim 23 wherein the sortable entity is flowed once through the detection region.

25. The method of claim 23 wherein:

the sortable entity is initially flowed through the detection region; and

then

a direction of flow is reversed to flow the sortable entity back into the detection region.

26. The method of claim 23 further comprising dampening an oscillation of energy within the flow channel upstream of the junction.

28. The method of claim 27 comprising using a reversible sorting process.

30. The method of claim 29 wherein the energy absorber comprises a flexible membrane that deflects into a cavity in response to the pressure oscillations.

31. The method of claim 29 wherein the energy absorber comprises a fluid pocket that experiences compression in response to the pressure oscillations.

32. The method of claim 29 wherein the energy absorber comprises an elastomeric flow channel sidewall that experiences deformation in response to the pressure oscillations.

33. The method of claim 29 further comprising constricting a width of the flow channel downstream of the energy absorber.

18. A damper for a microfluidic device comprising:

a flow channel formed in an elastomer material; and

an energy absorber adjacent to the flow channel and configured to absorb an energy of oscillation of a fluid positioned within the flow channel.

23. A sorting method comprising:

deflecting a first elastomer membrane of an elastomer block into a flow channel to cause a sortable entity to flow into a detection region positioned upstream of a junction in the flow channel;

interrogating the detection region to identify the sortable entity within the detection region;

based upon an identity of the sortable entity, deflecting one of a second membrane and a third membrane of the elastomer block into one of a first branch flow channel portion and a second branch flow channel portion located downstream of the junction to cause the sortable entity to flow to one of a collection pool or a waste pool.

29. A method for dampening pressure oscillations in a flow channel comprising providing an energy absorber adjacent to the flow channel, such that the energy absorber experiences a change in response the pressure oscillations.